The objective of this research is to determine the feasibility of developing a new absorbable mesh with prolonged strength retention for hernia repair. The product is expected to find application where current synthetic non-absorbable meshes provide poor outcomes, such as implantation in contaminated surgical fields, or in pediatric patients where they can hinder growth. It is also hoped that the product will lead to less occurrence of complications such as fistula formation, pain, and restriction of physical capabilities that can follow hernia repair procedures. The total number of patients that could benefit from this new mesh is large if it proves to be superior to existing options. Approximately, 1.5 million inguinal hernia repair procedures and 200,000 ventral hernia procedures are performed each year. The research approach will employ a new absorbable biomaterial, known as poly-4-hydroxybutyrate (also known as PHA4400), that has been shown to have prolonged strength retention in vivo compared to existing absorbable suture biomaterials. The specific aims of the project are to: (1) produce a melt extrudable grade of PHA4400; (2) extrude monofilament fiber of PHA4400 suitable for knitting into a hernia mesh; (3) prepare a monofilament knitted mesh of PHA4400 with a tensile strength comparable to commercial synthetic (polypropylene) hernia meshes; and (4) demonstrate that the in vivo mechanical stability of a hernia repair with a PHA4400 mesh at 3 months is greater than with an existing absorbable mesh (Vicryl TM) of comparable weight and density, make a preliminary comparison with the performance of a non-absorbable polypropylene mesh, and perform a morphological and histological study on samples from the implantation study to assess tissue reaction. In addition to developing a product that could improve surgical outcomes of hernia repair procedures, the research will also help to introduce a new absorbable medical biomaterial into the medical community that could find other uses, for example, in controlled release, tissue engineering, and other devices.